Here a hint in case anybody didn't find out yet:
On the Tortuga map, in the eastern part, near the Inferno is a guy called the "pit boss". He gives out 4 quests you can do which are called something like:
Pit Fight: One Wave of Enemies
Pit Fight: Two Waves of Enemies
Pit Fight: Three Waves of Enemies
Pit Fight: Crockodile!
I'm not sure what level you have to be to get the first of this group of quests or all of them, but you can do them once every 24 hours it seems and its a nice XP boost from level 40 or 45 on up to 50. To see if you can already do them, check on the Tortuga map if the "Pit Boss" npc is a star icon for you or a scroll one (the later means you can get quests from him).